A photo-coupler is one of the semiconductor devices. The photocoupler includes a light emitting element and a light receiving element, and transmits signals by optical coupling. The photo-coupler has various applications. A dual type photo-coupler includes two pairs of light emitting elements and light receiving elements, and has two transmission channels. This type of photo-coupler needs to suppress inter-channel crosstalk.
In such a device, the two light receiving elements may be bonded to a common lead, and two pairs of light emitting elements and light receiving elements may be molded within a single piece of resin for easing complexity in a fabrication. But the inter-channel crosstalk cannot be suppressed in such case. In another method, each pair of the light emitting element and the light receiving element is molded in an individual resin, and then molded together with a light blocking outer resin. This method may suppress the crosstalk. However, in the first molding step, a deformation may sometimes occurs in the portion of the common lead not sealed with resin. Thus, misalignment between the light emitting element and the light receiving element may be induced by the deformation, resulting in the wiring deformation and the reduction of optical coupling efficiency. Thus, there is demand for a semiconductor device capable of suppressing the inter-channel crosstalk and the misalignment between the light emitting element and the light receiving element, thereby improving the manufacturing yield.